<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script>
			function sum (a,b) {
				var c = a+b;
				return c;
			}
			var a =+ prompt("请输入:");
			var b =+ prompt("请输入:");
			var c = sum (a,b);
			console.log(c);
		</script>
	</head>
	<body>
	</body>
</html>
